The invention relates to a novel exhaust configuration specifically designed to reduce the noise level associated with operating a gasoline engine powered apparatus such as a blower or blower-vacuum apparatus ,improve operating efficiency and aid in the combustion of oil or unburned fuel that may be entrained within an exhaust stream.
In either of the aforementioned apparatus air is drawn into an air intake associated with a centrifugal fan. The air stream is then coupled to a volute shaped duct and exits the apparatus as a jet via a volute opening.
In the vacuum mode leaves and other debris is drawn in the air intake and traverses the volute duct and is collected in a bag attached to the volute opening. There is inherently a disturbing noise level associated with gas engine powered units through these come equipped with mufflers. The noise level generally increases with the horsepower. Blower-vacuum apparatus are often used over long periods of time. The noise is such that after a time the operator experiences discomfort and becomes fatigued. Often operators are advised to wear protective ear gear to prevent damage to the ears.
Most portable gas engines use a two cycle engine where lubricating oil is mixed directly with the gas and burned in the cylinder. Lubricating oil or unburned fuel which is not consumed within the cylinder generally clings to the walls of the muffler or exhaust pipe where it is usually burned. To the extent that unconsumed oil and fuel remains in the exhaust stream it is atomized within the exhaust stream. To the extent that this happens it can be messy. Oil can coat the apparatus, or surrounding surfaces with which the exhaust stream comes into contact.
The invention deals with a concept of coupling and merging the exhaust gases leaving the muffler of a gasoline engine with the air stream generated within the blower or the blower-vacuum apparatus for the purpose of reducing the noise level of apparatus and for improving the overall efficiency of the gas engine and for increasing or completing the combustion of oil within the engine.
The U.S. Pat. No. 1,331,649 to Kettering and the French patent No. 1,008,190 shows the mixing of exhaust gases in an air stream in an automobile environment. Specifically, these patents show the exhaust stream and air stream flowing in the same direction.
The U.S. Pat. No. 2,927,422 to Shaffer depicts an exhaust stream flowing in an air stream in a direction opposite to the air stream. In this case the exhaust stream is unconfined and distributed over a relatively large area and discharged against a relatively cool radiator core to extinguish sparks that may exist in the exhaust stream.